1. Field of the Invention
The present invention relates to a power adapter and, more particularly to a universal power adapter, which is selectively provided with one of a set of charging terminals to fit different voltage charging requirements.
2. Description of the Related Art
Following fast development of photoelectric, communication, and digital technology, a variety of sophisticate electronic products, such as PDAs, digital cameras, mini diskdrives, game machines, mobile phones, etc. have been disclosed and are commercially available. These portable electronic apparatus commonly use a battery to provide the necessary working voltage. However, when battery low, the battery must be recharged to the saturated status for continuous use. However, different battery chargers may have to be used to charge different mobile electronic apparatus subject to different voltage requirements. For example, the charging voltages of the mobile phones of Motorola, Nokia, Ericsson, Panasonic, etc., are different. Some need direct current of 4.2V, and some others need 4.5V. And the other products like PDAs or digital cameras have the same problem as well.
When one goes outside on business or trip, one may have to carry different battery chargers and transformers to fit different personal portable electronic apparatus.
The present invention has been accomplished under the circumstances in view. It is one object of the present invention to provide a universal power adapter, which selectively provides different output voltages to fit different voltage requirements. It is another object of the present invention to provide a universal power adapter, which is compact and highly mobile. To achieve these and other objects of the present invention, the universal power adapter comprises a power input connector, and a charging connector. The power input connector comprises a voltage regulator adapted to automatically regulate the voltage of input current. The voltage regulator comprises a power/signal jack for connection to the charging connector, a DC voltage converter adapted to convert input current into the desired voltage level and then transmit the voltage-converted input current to the power/signal jack, and a feedback control voltage output circuit adapted to drive the DC voltage converter to output a predetermined voltage subject to compare the feedback voltage signal obtained from the power/signal jack. The charging connector comprises a power/signal connecting connector at one end of the power cord thereof for connection to the power/signal jack and a voltage parameter preset therein.